Justify content start and end in bootstrap 4 with flex

I have this code, for a mobile header:

<div class="header_mobile">
    <div class="container">
        <div class="row">
            <div class="header_mobile_box">
                <div class="header_mobile_logo_div d-flex align-items-center justify-content-start">
                    <a href="<?php echo $host; ?>" title="<?php echo html($site_config['logo_text']); ?> - <?php echo html($site_config['logo_slogen']); ?>" class="header_logo_to_link navbar-brand">
                        <img src="<?php echo $host; ?>/images/assets/logo_33.png" alt="<?php echo html($site_config['logo_text']); ?> - <?php echo html($site_config['logo_slogen']); ?>" class="img-responsive header_logo_image" />
                    </a>
                </div>
                <div class="header_mobile_icons_div d-flex align-items-center justify-content-end">
                    <a href="<?php echo $host; ?>/kedvenc-termekeim" title="Kedvenc termékeim" class="header_kedvencek_link"><i class="fa fa-heart fejlec_kedvenc_ikon" aria-hidden="true"></i></a>
                    <a href="<?php echo $host; ?>/kosar" title="Kosár" class="header_kosar_link">
                        <i class="fa fa-shopping-basket fejlec_kosar_ikon" aria-hidden="true"></i>
                        <span id="header_kosar_text" class="header_kosar_text"></span>
                    </a>
                </div>
            </div>  
        </div>
    </div>
</div>

I gived the divs flex display and justify-content-start and end, but its not working, all the divs are at the left side, and under each other.

I also tryed: - giving the .header_mobile_box div: d-flex, and justify-content between, but still the same problem.

What am i doing wrong?